The invention relates to a method for operating a two-stroke engine that comprises a cylinder provided with a combustion chamber that is delimited by a reciprocatingly supported piston. The piston drives in rotation a crankshaft. A spark plug projects into the combustion chamber and ignites a fuel/air mixture in the combustion chamber. Devices for supplying fuel and combustion air into the combustion chamber are provided. A control unit determines ignition time by means of an ignition map wherein the ignition map indicates the ignition timing as a function of the engine speed for at least a first and a second operating states and for at least a first and a second engine speed ranges.
DE 38 17 471 C1 discloses a method for operating a two-stroke engine in which the ignition timing is set by means of an ignition map. At low engine speeds the ignition map has two characteristic lines, i.e., a characteristic line for the starting operation and a further characteristic line for normal (regular) operation of the two-stroke engine. When starting the engine, with increasing engine speed the ignition timing is advanced. In operation at low engine speeds the ignition timing is advanced when the engine speed decreases.
With this characteristic line control of the ignition timing, a very simple control for the ignition timing can be realized. However, it has been found that with this very simple control of the ignition timing the engine may stall in operation, in particular at low engine speed.